RE: [PATCH] clk: shmobile: r8a7795: Add USB-DMAC clocks

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Hi Geert-san,

> From: geert.uytterhoeven@xxxxxxxxx [mailto:geert.uytterhoeven@xxxxxxxxx] On Behalf Of Geert Uytterhoeven
> Sent: Monday, February 01, 2016 8:16 PM
> 
> Hi Shimoda-san,
> 
> On Mon, Feb 1, 2016 at 12:06 PM, Yoshihiro Shimoda
> <yoshihiro.shimoda.uh@xxxxxxxxxxx> wrote:
> >> From: geert.uytterhoeven@xxxxxxxxx [mailto:geert.uytterhoeven@xxxxxxxxx] On Behalf Of Geert Uytterhoeven
> >> > --- a/drivers/clk/shmobile/r8a7795-cpg-mssr.c
> >> > +++ b/drivers/clk/shmobile/r8a7795-cpg-mssr.c
> >> > @@ -124,6 +124,8 @@ static const struct mssr_mod_clk r8a7795_mod_clks[] __initconst = {
> >> >         DEF_MOD("pcie0",                 319,   R8A7795_CLK_S3D1),
> >> >         DEF_MOD("usb3-if1",              327,   R8A7795_CLK_S3D1),
> >> >         DEF_MOD("usb3-if0",              328,   R8A7795_CLK_S3D1),
> >> > +       DEF_MOD("usb-dmac0",             330,   R8A7795_CLK_S3D2),
> >> > +       DEF_MOD("usb-dmac1",             331,   R8A7795_CLK_S3D2),
> >>
> >> The datasheet is not very clear about whether the module clock is based of s3d1
> >> (266 MHz) or s3d2 (133 MHz), but given the comment "... it is recommended to
> >> allow several tens of clocks if operating at 260 MHz ..." in section 75.2.2
> >> "DMA0/1 Software Reset Register" of the datasheet, I'm inclined to believe s3d1
> >> would be correct.
> >
> > According to the HW team (in case of gen2 though):
> >
> > In gen2 (In gen3 I assumed)
> >  ZS (S3D1)     : For using DRAM access
> >  HP (S3D2)     : For using register access
> >  48MHz (50MHz) : For using USB transfer
> >
> > So, I also think that s3d1 would be correct.
> > What do you think?
> 
> Thanks, that makes two of us :-)
> Hence please use s3d1.

Thank you for the comment :)
I will submit v2 patch soon.

Best regards,
Yoshihiro Shimoda

> Gr{oetje,eeting}s,
> 
>                         Geert
> 
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
> 
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like that.
>                                 -- Linus Torvalds




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